This Background section is provided only to help explain some aspects of the invention and therefore may contain information that does not form prior art with regard to this patent application.
(a) Field of the Invention
The present invention relates to an apparatus and a method for converting image signals of a four-color display device.
(b) Description of the Related Art
In recent years, flat panel displays have been developed to replace heavy and large cathode ray tubes (CRTs). Examples of flat panel displays include organic light emitting diode displays (OLEDs), plasma display panels (PDPs), and liquid crystal displays (LCDs).
The PDPs display text and other images using plasma generated by gas discharge. The organic light emitting diode displays display images using field emission of specific organic materials (e.g. polymers). In a liquid crystal display, an electric field is applied to a liquid crystal layer interposed between two display panels. The intensity of the electric field is adjusted to control transmittance of light that passes through the liquid crystal layer, thereby obtaining a desired image.
A color flat panel display generally displays images by combining three primary colors of red, green, and blue, but a white pixel (i.e. without a color filter) is sometimes added to improve the luminance. This is called a four-color flat panel display. In the four-color flat panel display, the three-color image signals are received and converted into four-color image signals to display the image.
Disadvantageously, use of a white pixel may lead to distortion of hue and saturation.